Annual report pursuant to Section 13 and 15(d)

Organization and Summary of Significant Accounting Policies (Details)

v3.19.2
Organization and Summary of Significant Accounting Policies (Details)
 12 Months Ended
Apr. 30, 2010
USD ($)
Mar. 31, 2019
USD ($)
segment
Geographic_Region
Mar. 31, 2018
USD ($)
Mar. 31, 2017
USD ($)
Apr. 01, 2019
USD ($)
Business Acquisition [Line Items]          
Number of reportable segments | segment   4      
Accounts receivable, allowance for doubtful accounts (in dollars)   $ 987,000 $ 1,231,000    
Goodwill impaired   $ 0 $ 0    
Cost of selling controlling interest $ 129,252,000        
Disclosure on Geographic Areas, Long-Lived Assets in Foreign Countries   65.00% 68.00%    
Entity Wide Disclosure On Geographic Areas, Revenue From External Customers Attributed To Foreign Countries, Percentage   60.00% 63.00% 55.00%  
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]          
Amortization of Deferred Charges   $ 1,756,000 $ 1,657,000 $ 391,000  
Research and Development Expense   $ 6,289,000 5,240,000 3,501,000  
Number of Countries in which Entity Operates | Geographic_Region   4      
Group of investors and other private equity firms          
Business Acquisition [Line Items]          
Number of other private equity firms 2        
Land improvements | Minimum          
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]          
Property, plant and equipment, estimated useful lives   15 years      
Land improvements | Maximum          
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]          
Property, plant and equipment, estimated useful lives   20 years      
Buildings and improvements | Minimum          
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]          
Property, plant and equipment, estimated useful lives   10 years      
Buildings and improvements | Maximum          
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]          
Property, plant and equipment, estimated useful lives   40 years      
Machinery and equipment | Minimum          
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]          
Property, plant and equipment, estimated useful lives   3 years      
Machinery and equipment | Maximum          
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]          
Property, plant and equipment, estimated useful lives   25 years      
Office furniture and equipment | Minimum          
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]          
Property, plant and equipment, estimated useful lives   3 years      
Office furniture and equipment | Maximum          
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]          
Property, plant and equipment, estimated useful lives   10 years      
Internally developed software | Minimum          
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]          
Property, plant and equipment, estimated useful lives   5 years      
Internally developed software | Maximum          
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]          
Property, plant and equipment, estimated useful lives   7 years      
Allowance for Doubtful Accounts          
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]          
Balance, beginning of period   $ 1,231,000 518,000 656,000  
Reductions to expense   354,000      
Additions charged to expense     787,000 307,000  
Write-off of uncollectible accounts   (598,000) (74,000) (445,000)  
Balance, end of period   $ 987,000 $ 1,231,000 $ 518,000  
Predecessor | Group of investors and other private equity firms | Thermon Holding Corp.          
Business Acquisition [Line Items]          
Fair value of total consideration transferred $ 321,500,000        
Consideration transferred, liabilities incurred $ 210,000,000        
Accounting Standards Update 2016-02 | Scenario, Forecast          
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]          
Right of use asset         $ 21,000,000